Design and verification of intelligent temperature monitoring and cooling system for high-temperature fire area

In response to the existing problems in the temperature monitoring of boreholes in high-temperature fire areas of open-pit coal mines, this study proposed an intelligent temperature monitoring and early warning system by integrating fiber Bragg grating (FBG) temperature measurement with wireless communication and developing an automatic water injection cooling (failure) module. Based on similarity theory, we established a physical model for the rock strata of the fire area, and built a laboratory simulation system to simulate the temperature field distribution in the high-temperature fire area. Temperature at multiple points in the boreholes was monitored in real time by FBG sensors, and the temperature measurement data were transmitted via wireless communication. The reliability of this scheme was verified. Results show that compared with traditional thermocouple temperature measurement, FBG temperature measurement exhibited higher stability and measurement accuracy in high-temperature environments and could monitor and transmit temperature data in the boreholes in real time. Under varying initial temperature, when the heat release rate of the heat source was equal to the heat dissipation rate, the system automatically stopped water injection with the equilibrium temperature as the dynamic threshold. The cooling (failure) module could trigger water injection when the borehole temperature reached the corresponding high-temperature threshold (80, 90, 104 ℃), and the temperature dropped rapidly below the low-temperature threshold (60, 70, 90 ℃). The sensors near the borehole mouth showed temperature fluctuation attenuation of about 18% due to heat dissipation. The system thus forms a closed-loop solution featuring precise temperature measurement, intelligent early warning and rapid cooling.